One can’t do extreme sports _________ he or she has had some training.
#31217
A
if
B
unless
C
once
D
since
推荐题目
There are two spare rooms upstairs, ________ measures five meters across.
#33914
A
the larger of them
B
the larger of that
C
the larger of which
D
the larger of whom
 ______ I’m well again, I can go on with my work.
#33879
A
Even if
B
As though
C
Ever after
D
Now that